Protected packing seal



8 N f H, 6 E .o 2 /l I Mv W o m 1 Il M I* a4 R x 2 v3 M m D e m R. n n..IIIIXII |.II m w 7 @a 93 5. i M l. m p0 .m Y 02 M Y rcs PATENT oFFicEPRGTECTED PACKING SEAL Ralph liti. Harmon, Wichita, Kans., assignor toBeech Aircraft Corporation, Wichita, Kans., a corporation o DelawareApplication December 22, 1943, Serial No. 515,317

' 5 claims. Col. 28s-18) me invention here disclosed relates to packingseals for airplane landing gear shock struts, hydraulic actuatingcylinders and the like.

It is essential that all dirt and foreign matter be excluded from thepacking glands of such parts hereinafter set forth, illustrated by Wayof example in the accompanying drawing and broadly covered in theclaims.

ln the drawing, several of the present practical forms of the inventionare shown, but actual structure may be further modified and changed allwithin the trueintent and broad' scope of the invention as hereinatferdened and claimed.

Fig. l in the drawing, is a broken longitudinal sectional view slowngthe invention as applied to the so-called Oleo shock absorber landinggear strut of an airplane.

Fia'. 2 is an enlarged fragmentary detail of the same.

Fig. 3 is a similar view of a modification. Fig. It .is across-sectional detail as online 6-5 of Fis. 3. l

Fig. 5 is a broken longitudinal section of an-v other modiiied formofthe invention.

in Fig. l, the cylinder, barrel or bearing cap of a landing gear strutis indicated at l, and the co operating piston tube at B, operatingthrough the bearing provided by the gland nut S, acting on the packingik 1 This packing gland is sealed by a ring' H, ofsoit exible sealingmaterial, such as-leather, a

` composition of similar characteristics or a metallic composition,closely fitted to and engaging. the

polished surface of the piston tube. This seal, as particularly shown inFig. 2, may have an abrupt inner edge' and be resiliently confined ininclined relation, so Vas to provide a relatively rp corner edge inengagement with the tube.

In practice, the seal may be formed as anat washer with an insidediameter somewhat less than the diameter of the tubel and flanged out cithe plane of the washer, or it may be molded tube on an inward inclineand to provide at the outside of the ilange so formed, a 'seat for acontracting spring I2.

The seal made up of the washer and contracting spring is held in placeon the end of the gland nut by a retainer shown in the form of a ring,It3. secured by screws I4, and having a peripheral positioning flange l5,engageable over the reduced' endportion I6, of the nut.

The sealing washer is shown as seating partly in an annular positioningrecess Il, so that it may be clampingly held by the retainer ring andthe latter is shown as having an annular seat le, for the spring l2. Y

To protect the seal and maintain it in condition for properly sealingthe packing gland, a scraper is provided in iront of or at the outsideof the seal,

In the first form of the invention, this guard or protector is shown inthe form of a metal ring I9, having an inwardly inclined sharpened orchisel-like cutting or scraping edge 28, closely@ conforming to andsubstantially 'i engaging the surface oi the piston tube.

This scraper ring is shown as entered in enlarged portion 2i, in theouter end of the retainer i3, and held seated against a shoulder i2, bya. snap ring 23. v

Enclosed within and reinforced by the moimtv ing or retainer i3, thescraper ring can be a relatively small light piece and will be capableci cutting free any mud, dirt, ice or the like, on the piston tube,protecting and keeping the flexible seal in proper condition to performits wiping and `cleaning action.

helical compression spring, the rigid scraper or' any other part of themechanism.

The retainer and combined wiping and scraping structure confined orcarrled'thereby, occupies but small space at the end of the cylinder,where it is fully accessible and where it'willnot inter,- fere withother parts. I Y

'I'he modification illustrated in Figs. 3 and 4 diiiers from the rstform shown, particularly inrespect to the tensioning of the flexibleseal a suitable shape to thereby engage the piston Il, against thepiston tube.' In this instance, the

'. light in weight and takes up small space.

spring pressure is applied by a flat annular spring element 24,overlying the ilat .outer rim oi the flange portion of the seal.

Fig. 5 illustrates a forrm of the invention similaritc that tlrstdisclosed but having the inwardly inclined mud scraper ilange 26. formedas an integral portion of. the retainer ring 21.

In all forms. the structure is simple and sturdy, The

seal is soft or of suitable hardness and close iltting enough :to wipethe piston and keep it clean, and the scraper is sumciently rigid 'andstrong to loosen and break up m-ud, ice and like solids from the pistonprior to engagement of the piston by the soft, ilexible wiper sealingthe packvseal and having inwardly extending radial spring nngers 2B,pressing on the inwardly inclined ing, the gland nut having an annularseat at the entrance end of the same, the wiper being supported andpositioned on said seat, a retainer ring secured to the gland nut oversaid wiper and adjustable for tensioning the wiper against the pistonand the scraper being carried by said retainer ring and whereby both thewiper and the scraper may be removed upon separation of said retainerring from the gland nut.

foreign matter, protecting the seal from injury therein, 'packingbetween said cylinder and piston, a gland nut for compressing thepacking on the piston, awiper of soit, ilexible material tensioned in.wiping engagement with the piston at the entrance to said gland nut andforming a seal for the packing, and a scraper on the gland nut in frontof said wiper, said scraper being oi' stiil, rigid. material in scrapingrelation to the piston for removing adherent mud, ice or other solidsyfrom the piston prior to engagement of the piston by the soft, flexiblewiper sealing the packing.

2. A protected packing seal comprising in combination with a cylinderand a piston operating therein,- packing between said cylinder andpiston, a gland nut for compressing the packing on the piston, a 'wiperof soit, flexible material tensioned in wiping engagement with thepiston at the entrance to said gland nut and forming a seal for .thepacking, and a scraper on the gland nut in iront of said wiper, saidscraper being of stiil', rigid material in scraping relation to thepiston forremoving adherent mud, ice or other 3. A protected packingseal comprising in combination with a cylinder and a piston operatingtherein, packing between said cylinder and piston, a wiper of soft,flexible material supported by said cylinder and a retainer ringadjustably secured' over said wiper for tensioning said soft, ilexiblewiper in wiping engagement with the piston, said retainer ringv being o!rigid material and having an integral inwardly inclined mud scraperilange in scraping engagement with the piston at a point'in advance ofengagement of the piston by said soft, iiexible wiper.

4. A protected packing seal comprising in combination with a cylinderand a piston operating therein, packing between said cylinder and pis'-ton, al'wiper of soft, flexible material supported by 'said cylinder, aretainer ring adjustably secured in engagement over said wiper fortensioning said soft, ilexiblewiper in wiping engagement with 4 thepiston, and a scraper ring removably mount- @with said piston andforming a seal for said packing and a scraper of stiff, rigid materialsupport ed by the cylinder in scraping relation to the piston in advanceof said wiper for clearing the piston of adherent mud, ice or othersolids prior to engagement oi' the piston by said soit, flexible wiper.

RALPH M. HARMON.

